1. Field of the Invention
The present disclosure relates generally to packet network devices, and more particularly to intelligent power management of a distributed platform for such a device.
2. Description of Related Art
Packet network devices such as switches and routers receive packets at a plurality of external ports, and forward those packets out other external ports, as appropriate, to advance the packets toward their network destinations. Medium-to-large switch/routers (e.g., more than 50 ports) typically employ a modular design, with a plurality of cards that plug into slots in a backplane, and communicate through the backplane.
FIG. 1 shows a high level block diagram for a modular switch/router 100, including some components thereof. The components shown include line cards LC0, LC1, LCn, router processor manager (RPM) cards RPM0, RPM1, and a backplane 110. Packets are received into and transmitted from switch/router 100 through the external ports on line cards LC0, LC1, and LCn, and are forwarded through switch/router 100 on a data plane (not shown; the data plane may include line card forwarding circuitry, which communicates through backplane signaling connections with separate switch fabric cards and/or a switch fabric on the RPMs). Within the chassis, the line cards and RPM cards pass control plane data through backplane connections that are separate from the data plane connections.
In this example, the control plane connections include a backplane Ethernet bus BPE and a backplane I2C (Inter-Integrated Circuit) two-wire bus. The backplane Ethernet bus couples Ethernet ports (EP0, EP1, EPn) on the line cards with Ethernet switches (ESWR0, ESWR1) on the RPMs. The Ethernet ports connect respectively to line card processors (LCP0, LCP1, LCPn) on the line cards, and the Ethernet switches connect respectively with control card processors (RCP0, RCP1) on the RPMs. This allows the control card processors to communicate with the line card processors using appropriately addressed internal packets, in order to exchange configuration data, routing/switching updates, line card software images, and heartbeat messages.
The I2C bus also connects the control card processors (RCP0, RCP1) on the RPMs with components on the line cards. For instance, software running on the control card processors can use the I2C bus to poll temperature monitors (TM0, TM1, TMn) and voltage monitors (VM0, VM1, VMn), one at a time, for line card environmental statistics. Other devices on the line cards are typically monitored in similar fashion.